Method of making composite



Dec. 3, 1935. F. F. BRUCKER v y METHOD OF MAKING COMPOSITE ARTICLES Filed Feb. 4, 1932 Patented Dec. 3, `1935 UNITED STATES PATENT OFFICE METHOD OF MAKING COMPOSITE ARTICLES Application February 4, 1932, Serial No. 590,805

501mm.v (ci. zei-155.5)

l the article to each other, to provide against tarnishing of the metal parts during manufacture, to provide against breakage during manufacture and to provide simplicity and eiliciency in structure.

15 Other objects will appear from the following description and theaccompanying drawing.

In the drawing,in which, by way of example, I have illustrated an electrical attachment plug and its method of manufacture.

20 Fig. 1 is a central cross-sectional view of an attachment plug showing in dotted lines the contact bladesl and the tools for attaching them to the other parts.

Fig. 2 is a similar view showing the contact 25 blades in place and the insulating plugs, one of the plugs being inserted and the other ready to insert. v

Fig. 3 is a cross sectional view on line 3-3 of Fig. 2.

30 Referring to the drawing, the numeral I0 designates the body of an attachment plug which may be molded from plastic insulating material to provide a body of flexible material, but preferably of soft rubber. This body may be formed 35 with a passage II therethrough to afford a passage for insulated wires and with recesses I2 for holding the wires. A tubular handle I3 may also be provide to assist in inserting or withdrawing the plugiI Inserts Il, of soft metal 40 are partially enclosed in the body I0 during the molding thereof and may be adherently attached to the plastic material by any of the well known processes. Where the body IU is formed of soft rubber, the inserts Il may be made of a brass composition or-may be electroplated with a brass composition to which the rubber will oe rmly attached by vulcanization.

The inserts I4 may be grooved as at I5 to interlock with the plastic material and afford 50 an increased adhesive surface.

In order to facilitate accurate location of the inserts I4 in the body III, the inserts are provided with central longitudinal passages I6 which nt over shouldered supporting pins provided in 55 the mold which forms the body portion. Such pins form openings I1 through the body below the inserts Il and are preferably so formed as to provide annular grooves I8 in said openings where th(` #dy is to be formed of soft rubber.

It is well known that where metal parts are heated in contact with plastics such as rubber, as during vulcanization of the rubber thereto, the metal parts become oxidized or tarnished by combining with sulfur or other chemicals present in the plastic material. It is also well known 10 that such oxidized or tarnished surfaces are not electrically eiiicient as conductors. In order to avoid the presenceof oxides or sulfldes on the surfaces of the metal parts I provide separate current conducting parts and attach these to the metal inserts embedded in the body portion after the forming of the body portion is complete.

In the attachment plug shown as an example, the contact blades I9 are provided with integral current conducting bases adapted to be seated 20 on the body I0 and provided with openings 2| which embrace reduced ends 22 of inserts Il. Bases 20 are also provided with threaded openings for receiving conductor-clamping screws 23. The reduced ends 22 of the inserts are upset as 25 at 24 by riveting or spinning so as to permanently retain the blades in place.

Where the base I0 is made of brittle material, the riveting of contact blades or other metallic members to inserts supported only by the base is conducive of cracking of the base and where the base is made of resilient material such as soft rubber it is impossible to rivet to an insert supported on such resilient material. In order to obviate these difficulties I form the base with the openings I'I in line with the inserts Il and of suiiicient size to admit supporting anvil members 25 provided with dowels 26. The anvil members are firmly supported in a die block 21 mounted in a punch press or other pressure device 40 where punches 28 mounted in line with the anvil members, may be used to upset the tubular rivet extensions of inserts I4 without producing distorting stresses in the base Ill.

After the contact blades have been attached openings I1 may be closed by filling plugs 29 of soft rubber. These plugs may be beaded as at 30 to interlock with grooves I8 and may if' desired be coated with cement before being put in place. 'I'he closing of opening I1 prevents elec- 50 trical contact being made with inserts Il from. the back of the plug.

The insert supporting pins in the mold correspond to the anvil members 25 and where desired the blades may be riveted to the inserts while the same are in the forming mold after the plastic parts have been molded therein.

I claim:

l. 'I'he method of making a composite article of metal and moldable plastic material which comprises molding a resilient body from plastic material and simultaneously embedding a metal insert therein and forming an opening back of said insert, and supporting saidl insert through said opening while attaching a metal part thereto by pressure applied through said insert without subjecting the body to pressure.

2. The method of making a composite article of metal and moldable plastic material which comprises supporting a metal insert in a mold, molding a resilient body of plastic material thereabout, removing the article so formed from the mold, and supporting the insert through an opening in the body while attaching a metal part thereto without subjecting the body to pressure.

3. 'I'he method of making a composite article o! rubber and metal which comprises supporting a metal insert in a mold, forming and vulcanizing a resilient rubber body around said insert and attaching a metal part to said insert by pressing dies one of which directly supports the insert through an opening in said body Without subjecting the body to pressure.

4. The method of making an attachment plug which comprises supporting a plurality of metal inserts in a mold, forming a body of soft, vulcanized rubber thereabout, and riveting a metal contact blade to each insert while directly supporting the insert through an opening in said body without subjecting the body to pressure.

5. The method of making a composite article which comprises forming a resilient body of plastic rubber compound around a metal insert while supporting said insert on a pin passing through said body, and riveting a metal part to a projecting portion of said insert While said insert is so supported without subjecting the body 20 to pressure.

FERDINAND F. BRUCKER. 

